Filter construction and method of forming same

ABSTRACT

A filter is provided for attachment to the downstream end of a tobacco rod. The filter includes a unitary core piece formed from a single blank of sheet material and a sleeve unit encompassing said core piece and cooperating therewith to form a shallow passageway through which smoke is caused to flow subsequent to having impinged at a high velocity against a surface forming the passageway.

Killed States Patent [151 3,640,27 Pinlsham Feb. 8, 1972 [54] FILTER CONSTRUCTION AND 3,335,733 8/1967 Brooks ..l3l/26l B METHOD OF FORMING SAME 3,394,707 7/1968 Ellis ..131/10.s 3,394,713 71968 Tho t l. ..131210X 72 Inventor: Jesse R. Pinkham, Winston-Salem, NC. I 6 a I [73] Assignee: R. J. Reynolds Tobacco Company, Win- FOREIGN PATENTS OR APPLICATIONS ston-Salem, N.C. 554,810 3/ 1923 France [22] Filed: Sept. 22, 1969 Primary ExammerSamuel Koren PP No.2 ,968 Assistant Examiner-J. F. Pitrelli 1 Attorney-Pendleton, Neuman, Anderson & Williams [52] U.S.Cl ..l31/26l B, 131/201, 131/210 [51] Int. Cl ..A24d 01/04, A241 07/04, A24f 13/06 ABSTRACT [58] held of Search ..131/1().5, 201, 210, 261 B; A filter is provided for attachment to the downstream end of a 93/1 C tobacco rod. The filter includes a unitary core piece formed 56 R i (ed from a single blank of sheet material and a sleeve unit encom- 1 e new I passing said core piece and cooperating therewith to form a UNITED STATES PATENTS shallow passageway through which smoke is caused to flow subsequent to having impinged at a high velocity against a sur- ,5 1 Crawford l 3 l l l face forming the passageway 2,954,787 10/1960 Lebeit ..131/10.5 X 3,236,243 2/1966 Robins ..13 l/210 X 9 Claims, 9 Drawing Figures BACKGROUND OF THE INVENTION Filter cigarettes have become increasingly more popular with the smoking public and as a result it is necessary that the production thereof be maintained at an exceedingly high rate in order to meet this demand. Because of these factors, it is important that the filter utilized in such a cigarette (a) be formed of a minimum number of component parts, (b) that the parts be of simple and inexpensive construction, (c) that the various component parts be capable of being expeditiously assembled by automatic equipment, the function and operation of which are well known by those skilled in the cigarettemaking art, (d) that the formation and/or production of the component parts be maintained at a rate which is substantially commensurate with the rate of production of the tobacco rods, and (e) that each filter be effective in operation and have substantially uniform filtering characteristics.

SUMMARY OF THE INVENTION Thus, it is an object of this invention to provide a filter which meets the aforenoted requisites.

It is a further object of this invention to provide a filter wherein the components thereof may be formed at the time the filter is to be attached to the end of the tobacco rod.

It is a still further object of this invention to provide a filter wherein the size and shape thereof may be varied so as to accommodate tobacco rods of various sizes.

It is a still further object of this invention to provide a filter which is readily expendable and in no way detracts from the appearance of the cigarette or impairs the taste and aroma of the smoke.

Further and additional objects will appear from the descrip tion, accompanying drawings and appended claims.

In accordance with one embodiment of this invention, a filter is provided which is adapted to be attached to the downstream end of a tobacco rod. The filter includes a core piece formed from a single blank of sheet material, and a sleeve unit which encompasses the core piece. A portion of the sleeve unit is disposed in spaced relation with respect to a corresponding portion of the core piece so as to form a shallow passageway through which smoke is caused to flow sub sequent to having impinged at a high velocity against a surface forming the passageway.

DESCRIPTION For a more complete understanding of the invention reference should be made to the drawings wherein:

FIG. 1 is a fragmentary vertical sectional view of one form of the improved filter shown affixed to the downstream end of a tobacco rod.

FIG. 2 is a fragmentary perspective view of the'core piece shown in FIG. 1 with spacer strips applied thereto; portions of the core piece and strips being cut away to show the interior configuration.

FIG. 3 is a fragmentary top plan view of a web for making the core piece of FIG. 2.

FIGS. 4 and 5 are fragmentary perspective views showing the web of FIG. 3 in various stages of formation.

FIG. 6 is a fragmentary top plan view of a web for making a modified form of core piece.

FIG. 7 is a fragmentary side elevational view of the modified core piece made from the web of FIG. 6 and with a portion cut away to expose the interior thereof.

FIG. 8 is an enlarged sectional view FIG. 7.

FIG. 9 is a schematic side view of a portion of the apparatus for forming the modified core piece of FIG. 7.

Referring now to the drawings and more particularly to FIG. 1, one form 10 of the improved filter is shown affixed to the downstream end 11 of a tobacco rod 12. Filter 10 includes a core piece 13, see FIG. 2, an outer sleeve unit 14, which may taken along line 8-8 of be formed of conventional tipping paper, and an intermediate spacer unit 15, the latter serving to retain corresponding portions of the core piece 13 and outer sleeve unit 14 in spaced relation so as to form a shallow passageway P (e.g., 0.012 inch), which encircles the core piece 13. The outer sleeve unit 14 has one end thereof adhesively secured to and in encompassing relation with the rod end 1 l.

The illustrated core piece 13 is formed from a web 16 of suitable paper stock, as seen in FIG. 3. It is to be understood, of course, that webs of other configurations may be utilized. The web, as shown, is provided with a plurality of longitudinally spaced, pairs of semicircular slits 17a and b and 18a and b. Each pair of slits is inverted relative to the succeeding pair.

In addition to the slits, the web 16 is provided with three longitudinally extending, equally spaced, parallel foldlines 20, 21 and 22. The center foldline 21 extends between the slits 17a and b and 18a and b comprising each pair of slits. The other foldlines 20 and 22 interconnect the corresponding end limits of slits 17a-18a and 17b-18b, respectively. Each slit has the end limits thereof terminating at a foldline 23 which is transversely disposed relative to foldlines 20, 21 and 22.

Extending transversely outwardly from foldline 22 are rows of perforations 24 and 25. Extending transversely in the opposite direction from foldline 20 are rows of perforations 26. Each row of perforations 26 is aligned with a row of perforations 25 so that when the web 16 is set up to form the core piece 13, the two aligned rows will cooperate so as to form a single row of perforations which encircles the piece 13. The total number of perforations 25 and 26 comprising the encircling row is normally greater than 12.

In forming the core piece 13, the web 16 is initially folded about foldlines 20, 21 and 22 so as to assume an inverted T- configuration, see FIG. 4. When the web is in this state, the portions and b of the web, which are disposed between foldlines 20 and 21, and 21 and 22, respectively, are arranged in face-to-face relation by adhesive. The slits 17a and 18a of web portion 16a are in registration with the corresponding slits 17b and 18b of portion 16b when the partition 27 is formed.

Subsequent to the forming of central partition 27, tabs or smoke barrier panels 28 and 30 are struck out in opposite directions from the partition 27, see FIG. 5, and assume positions normal thereto. After the tabs have assumed the positions shown in FIG. 5, the portions 160 and d of the web disposed outwardly of foldlines 20 and 22, respectively, are folded about the respective foldlines so as to form a sleeve or cylindrical unit 31 in which the partition 27 is diametrically disposed and the tabs 28 and 30 are in sealing engagement with the interior surface of the formed sleeve unit 31. The upper edge of the partition 27 is also in sealing engagement with the sleeve interior surface. The outer edges of portions 160 and d are adhesively retained in overlapping relation, not shown, once the sleeve has been formed.

It will be noted in FIGS. 1, 2 and 5 that the segment X of the partition 27, which is disposed between the adjacent tabs 28 and 30 forming the core piece 13, is imperforate. This arrangement is important because the smoke, upon being withdrawn from the tobacco rod end 1 1 through the filter, first passes along both sides of the partition 27; however, the smoke on one side of the partition impinges the upstream face of tab 30 and is diverted thereby so as to pass through the void 32 formed in the partition when the tab 30 is struck out. Thus, after the smoke passes through the void 32, it becomes accumulated between the partition segment X and the interior surface of sleeve-forming web portions 16d. The accumulated smoke is prevented from further axial flow, however, by the tab 28 and therefore must pass radially outwardly through perforations 24. Because of the configuration of the portion of the filter in which the smoke is accumulated, prior to passing through perforations 24, it is necessary that the row of perforations only partially encircles the sleeve unit 31 (i.e., this is to one side of the partition 27).

The perforations 24 are of a very small size (e.g., 0.0102- inch diameter) so that the smoke will attain a high velocity as it passes therethrough. Due to its high velocity, the smoke upon entering the shallow passageway P impinges against the interior surface of sleeve unit 14 and causes the solid and/or liquid particles entrained in the smoke to be deposited on the said interior surface. Upon reaching the downstream end of the passageway P, the smoke is diverted by the spacer l5 and is caused to flow inwardly through the row of perforations 25. The latter perforations are normally larger than perforations 24, so as to minimize the pressure drop across the filter. It is desirable that the pressure drop across the filter not exceed approximately 3.5 inches of water.

The spacers which determine the shallowness of passageway P may be strips of paper which are adhesively applied in encircling relation on the exterior surface of the core piece sleeve 31.

The void 33, which is formed in the core piece partition 27 and is located downstream of tab 28, does not impede the smoke flow through the remainder of the filter 10.

In forming the core piece 13, a section of web 16 of predetermined length is formed into an elongated tubular member. To the exterior surface of the tubular member are applied the desired number of spacer strips 15. Following the application of the strips, core pieces 13 of the desired length are cut therefrom by suitable cutter blades, not shown. The core piece is then placed in abutting end-to-end relation with the downstream end 11 of the rod 12 whereupon the tipping paper is applied so as to form the outer sleeve unit 14.

FIGS. 7-8 show a modified form of core piece 13 which is adapted to be substituted for core piece 13 shown in FIGS. 1 and 2. Core piece 13' is cut from an elongated tubular member 34 which has been formed from a web 16' of suitable paper stock. The web 16', prior to being formed into tubular member 34, passes beneath a slitter roll 35 which forms therein a plurality of longitudinally spaced, crescent-shaped slits 36 arranged along a central axis. Either prior or subsequent to web 16 passing beneath slitter roll 35, it may pass between suitable perforating rolls, not shown, wherein substantially elliptical longitudinally spaced rows of perforations A are formed in the web, see FIG. 6. The shaping of each row is such that the perforations A thereof are disposed at a substantially uniform distance (e.g., 0.0l2 inch) from the curved interior surface of the remainder of the web, when said web is formed into the tubular member 34.

In forming the tubular member 34, the elongated edges of the web are first brought into adhesively secured overlapping relation, see FIG. 8. Subsequent to the web edges assuming an overlapping relation, the tubular member is caused to pass over (or beneath) a forming wheel 37, which is provided with a plurality of uniformly spaced lugs 38. Each lug is of the same configuration and has a rounded or shaped leading edge 38a which is adapted to initially engage the tonguelike portion 39 of the web 16' defined by the slit 36. To assure proper registration of the tonguelike portions 39 with the lugs 38, the tubular member 34 is fed between guides 40a and b. The extent to which each lug 38 projects from the wheel periphery corresponds substantially to the interior diameter of the tubular member 34 so that as the wheel rotates each lug will deform inwardly the tonguelike poru'on, as seen more clearly in FIG. 7. The peripheral shape of portion 39 is such that it will frictionally engage the interior surface of the tubular member disposed opposite the portion. If desired, adhesive may be utilized to retain the portion 39 in its deformed position. The tubular member 34 is then cut into segments of appropriate lengths which comprise core pieces 13'. Each core piece 13' is then attached to the downstream end of the tobacco rod by suitable tipping paper, not shown, which encompasses the core piece. The perforations A formed in the deformed portion 39 provide the means for the smoke to pass through the filter. The size and location of the perforations A are such that the circulating smoke will attain ahigh velocity as it passes through the perforations and will impin e against the interior surface of the encompassing portions 0 the web downstream of the slit. By reason of the smoke impingement, the liquid and/or solid particles entrained in the smoke will be deposited on the interior surface.

Thus, when utilizing any of the core pieces aforedescribed, an effective filter of simple and inexpensive design is provided which may be readily formed and assembled with automatic equipment, the function and operation of which are well understood in the cigarette-making art. The component parts of the improved filter are formed at the same time and rate as the tobacco rod is formed, thus, eliminating the cost and difi'rculty associated with filters wherein certain components thereof must be formed in advance by injection molding or the like.

I claim:

1. In a filter having a sleeve unit attachable to the downstream end of a tobacco rod, a smoke barrier piece positionable within the sleeve unit, said piece being formed from a blank of smoke-impervious sheet material and comprising a tubular member, and baffle means cut from said blank and angularly disposed within said tubular member, said angularly disposed bafile means including a panel extending substantially transversely to the axis of said tubular member and having an arcuate periphery in sealing contact with the interior surface of said tubular member whereby axial flow of smoke throughout the interior of said tubular member is blocked by said bafile means.

2. The smoke barrier piece of claim 1 wherein said bafile means includes an axially extending transverse partition separating at least a portion of said tubular member interior into a pair of elongated compartments and from which the panel is cut and extends into one of the compartments and having the arcuate periphery of said panel in sealing engagement with the portion of the tubular member interior surface defining said one compartment, and a second panel cut from said partition and extending into the second of said compartments, said second panel having an arcuate periphery in scaling engagement with the portion of the tubular member interior surface defining said second compartment, said cut panels being in axially spaced relation and separated from one another by an imperforate segment of said partition.

3. The smoke barrier piece of claim 2 wherein said partition extends diametrically across said tubular member and forms the interior thereof into a pair of compartments of substantially like cross-sectional configuration.

4. The smoke barrier piece of claim 3 wherein said partition is of multi-ply construction.

5. The smoke barrier piece of claim 1 wherein said baffle means is cut from a segment of the wall defining said tubular member.

6. The smoke barrier piece of claim 5 wherein said baffle means is provided with a perforation through which smoke is adapted to pass therethrough at a high velocity; said perforation being disposed in close proximity to a portion of the remainder of the wall defining said tubular member whereby the high-velocity smoke passing through said perforation will impinge against the adjacent tubular member wall portion.

7. The smoke barrier piece of claim 1 wherein said blank is smoke impervious paper.

8. The smoke barrier piece of claim 1 wherein at least a portion of the baffle means periphery is bonded to the interior surface of said tubular member.

9. The smoke barrier piece of claim 1 wherein said tubular member includes a plurality of perforations on each side of the line of contact between the baffle means and said interior surface. 

1. In a filter having a sleeve unit attachable to the downstream end of a tobacco rod, a smoke barrier piece positionable within the sleeve unit, said piece being formed from a blank of smokeimpervious sheet material and comprising a tubular member, and baffle means cut from said blank and angularly disposed within said tubular member, said angularly disposed baffle means including a panel extending substantially transversely to the axis of said tubular member and having an arcuate periphery in sealing contact with the interior surface of said tubular member whereby axial flow of smoke throughout the interior of said tubular member is blocked by said baffle means.
 2. The smoke barrier piece of claim 1 wherein said baffle means includes an axially extending transverse partition separating at least a portion of said tubular member interior into a pair of elongated compartments and from which the panel is cut and extends into one of the compartments and having the arcuate periphery of said panel in sealing engagement with the portion of the tubular member interior surface defining said one compartment, and a second panel cut from said partition and extending into the second of said compartments, said second panel having an arcuate periphery in sealing engagement with the portion of the tubular member interior surface defining said second compartment, said cut panels being in axially spaced relation and separated from one another by an imperforate segment of said partition.
 3. The smoke barrier piece of claim 2 wherein said partition extends diametrically across said tubular mEmber and forms the interior thereof into a pair of compartments of substantially like cross-sectional configuration.
 4. The smoke barrier piece of claim 3 wherein said partition is of multi-ply construction.
 5. The smoke barrier piece of claim 1 wherein said baffle means is cut from a segment of the wall defining said tubular member.
 6. The smoke barrier piece of claim 5 wherein said baffle means is provided with a perforation through which smoke is adapted to pass therethrough at a high velocity; said perforation being disposed in close proximity to a portion of the remainder of the wall defining said tubular member whereby the high-velocity smoke passing through said perforation will impinge against the adjacent tubular member wall portion.
 7. The smoke barrier piece of claim 1 wherein said blank is smoke impervious paper.
 8. The smoke barrier piece of claim 1 wherein at least a portion of the baffle means periphery is bonded to the interior surface of said tubular member.
 9. The smoke barrier piece of claim 1 wherein said tubular member includes a plurality of perforations on each side of the line of contact between the baffle means and said interior surface. 